Increased adoption of biometrics security in mobile phones, close-circuit television and other consumer applications spurred revenue growth in the global market for infrared LEDs from $201.5m in 2014 to $241.4m in 2015, according to Jamie Fox, principal analyst, LEDs and Lighting, at IHS Markit. While infrared LEDs grew 19.8% year-on-year in 2015, the overall infrared components market fell by 9%. Osram, Everlight and Vishay were the leading suppliers.
Common infrared LED that emits infrared rays has the same appearance with visible light LED. Its appropriate operating voltage is around 1.4v and the current is generally smaller than 20mA. Current limiting resistances are usually connected in series in the infrared LED circuits to adjust the voltages, helping the LEDs to be adapted to different operating voltages.
An IR LED, also known as IR transmitter, is a special purpose LED that transmits infrared rays in the range of 760 nm wavelength. Such LEDs are usually made of gallium arsenide or aluminium gallium arsenide. They, along with IR receivers, are commonly used as sensors.
The appearance is same as a common LED. Since the human eye cannot see the infrared radiations, it is not possible for a person to identify whether the IR LED is working or not, unlike a common LED. To overcome this problem, the camera on a cellphone can be used. The camera can show us the IR rays being emanated from the IR LED in a circuit.